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Identification of substrates of the CRL4-HBx E3 ubiquitin ligase

ABSTRACT: Hepatitis B Virus (HBV) remains a major public health problem, and is a major cause liver cancer worldwide. HBV infection in vivo requires the function of the HBx protein, which facilitates expression of viral genes from the episomal genome by an unknown mechanism. Evidence suggests that HBx functions as a targeting subunit for the CRL4 E3 ubiquitin ligase, redirecting the complex to target and degrade an unknown host restriction factor. We used substrate trapping proteomics to search for ubiquitylation substrates of HBx. We used MLN4924 to block CRL activity and stabilize interactions between HBx and its substrates. We then performed APMS to identify bound proteins and potential substrates.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Hepatocyte, Cell Culture

SUBMITTER: Christopher Murphy

LAB HEAD: Lishan Su

PROVIDER: PXD004762 | Pride | 2016-09-29

REPOSITORIES: Pride

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Hepatitis B Virus X Protein Promotes Degradation of SMC5/6 to Enhance HBV Replication.

Murphy Christopher M CM Xu Yanping Y Li Feng F Nio Kouki K Reszka-Blanco Natalia N Li Xiaodong X Wu Yaxu Y Yu Yanbao Y Xiong Yue Y Su Lishan L

Cell reports 20160901 11

The hepatitis B virus (HBV) regulatory protein X (HBx) activates gene expression from the HBV covalently closed circular DNA (cccDNA) genome. Interaction of HBx with the DDB1-CUL4-ROC1 (CRL4) E3 ligase is critical for this function. Using substrate-trapping proteomics, we identified the structural maintenance of chromosomes (SMC) complex proteins SMC5 and SMC6 as CRL4(HBx) substrates. HBx expression and HBV infection degraded the SMC5/6 complex in human hepatocytes in vitro and in humanized mice ...[more]

PMID: 27626656

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